Space/time is actually One and everything is happening in the eternal moment of Now. But yes, past present and future were created as perceptions because we can't handle everything happening at once. Made not just by man, but the whole Oneness of everything so we can experience life.

We exist in time and such are surrounded by all kinds of happenings, things going on all about just as we happen in respect of these things that happen.

So long as there is change from this moment to the next, and there is a string of such moments, I think one cannot discount the notion of past or future nor of the present; they have meaning for us and as such exist.

It may not be possible to disentangle those notions from the notion of locality. That there is no global sense of time, and that everything is happening in its very own time. I think it was shown in General Relativity to be true.

We tend to think of time as a constant but that is far from the case. In Einstein's view everything is relative. Our concept of time allows us to plan and control our lives to a certain extent. It's the probability factor which changes.

The future is the most uncertain, the present is the most certain. Certainty, like time, is a man made concept and in this world nothing is certain

How could time differ from the past, present, and future? They are all concepts. (Made by man, and perhaps made by other concept-forming beings.) Are things real only when they exist physically, or is it enough for them to exist non-physically as ideas?